Source: WASHINGTON STATE UNIVERSITY submitted to NRP
PREPARING U.S. POME FRUIT PRODUCTION FOR EXTREME TEMPERATURES IN A CHANGING CLIMATE
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
ACTIVE
Funding Source
OTHER GRANTS
Reporting Frequency
Annual
Accession No.
1032988
Grant No.
2024-51181-43289
Cumulative Award Amt.
$6,748,437.00
Proposal No.
2024-05458
Multistate No.
(N/A)
Project Start Date
Sep 1, 2024
Project End Date
Aug 31, 2028
Grant Year
2024
Program Code
[SCRI]- Specialty Crop Research Initiative
Recipient Organization
WASHINGTON STATE UNIVERSITY
240 FRENCH ADMINISTRATION BLDG
PULLMAN,WA 99164-0001
Performing Department
(N/A)
Non Technical Summary
Extreme temperatures that deviate from seasonal norms are increasing in frequency because of climate change. These changes will increase the risks of devastating crop losses, like those experienced for apple and pear crops over the last two decades. These losses urgently need to be reduced. However, our knowledge of apple and pear responses to temperatures is insufficient. Our current knowledge is largely derived from few cultivars that are now less commercially relevant. The industry needs mitigation strategies for current cultivars and knowledge to quickly assess new cultivars to determine if they are suitable for future climates. Goals 1 and 2 deliver management strategies that reduce risk of losses to extreme temperatures based on a better understanding of the physiological responses to extreme temperatures for economically important apple cultivars. These goals will alsoallow for the selection forkey traits affecting responses to extreme temperatures.Goal 3 will provide cost-benefit analysis that increases grower adoption of management strategies tested in Goals 1 and 2. It will also develop predictive models for risks of temperature-related losses in the future under climate change. Goal 4 will integrate research personnel with stakeholders to develop unified Extension programming that prepares the pome fruit industries in the U.S. for the challenges of climate change. This project will help sustain the U.S. as a leader in pome fruit production, strengthening the rural economy and providing consumers with a consistent supply of quality fruit produced in efficient and sustainable ways.
Animal Health Component
50%
Research Effort Categories
Basic
20%
Applied
50%
Developmental
30%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2031119102020%
2011119108015%
2051119102020%
2061119105015%
1321119207020%
6011119301010%
Knowledge Area
601 - Economics of Agricultural Production and Farm Management; 206 - Basic Plant Biology; 203 - Plant Biological Efficiency and Abiotic Stresses Affecting Plants; 205 - Plant Management Systems; 132 - Weather and Climate; 201 - Plant Genome, Genetics, and Genetic Mechanisms;

Subject Of Investigation
1119 - Deciduous tree fruits, general/other;

Field Of Science
2070 - Meteorology and climatology; 1080 - Genetics; 3010 - Economics; 1020 - Physiology; 1050 - Developmental biology;
Goals / Objectives
GoalsReduce apple and pear losses from current and future extreme temperature events by supporting growers to select the best mitigation strategies and new cultivars that will succeed in a changing climate1.Reduce losses to apple and pear productivity and health from low temperature stress.2. Reduce the negative impact of high temperatures during summer/fall on fruit quality in pome fruit.3. Model the risks and economic impacts of temperature extremes to inform decision making by commercial apple and pear producers.4. Develop nationwide Extension programming to help growers manage orchard responses to adverse temperatures and prepare them for the effects of climate change on production.
Project Methods
Goal 1 -Reduce losses to apple and pear productivity and health from low temperature stress Here, we will characterize the phenotypic plasticity, transcriptomic response, and genetic architecture of winter physiology in pome fruit and develop management strategies that reduce losses.Objective 1.1. Assess cultivar-specific cold hardiness patterns and management strategies to reduce losses from cold temperature stress for apple and pearTask 1.1.1: Measure seasonal hardiness changes in apple and pear cultivarsTask 1.1.2: Characterize the impact of variable freeze damage on apple shoot recovery and mortality.Task 1.1.3: Evaluate strategies to increase flower bud cold hardiness during spring frost for current apple and pear cultivarsObjective 1.2: Characterize physiological changes in flower buds and stems during acclimation, dormancy, deacclimation, and budbreak in apple and pearTask 1.2.1. Measure cold hardiness and dormancy status of apple flower budsTask 1.2.2: Measure cold hardiness, assess dormancy status, and investigate transcriptional profiles of pear flower budsTask 1.2.3: Measure effects of snow cover insulation on scion and rootstock cold hardiness and associated gene expressionObjective 1.3: Unravel the genetic control of chilling requirement, budbreak, and bloom time for appleTask 1.3.1: Characterize phenotypic variation in scion chilling requirements among segregating rootstock linesTask 1.3.2: Evaluate engineered rootstocks with enhanced ABA synthesis for their ability to delay scion budbreakTask 1.3.3: Determine genetic control and variability in budbreak and bloom time in apple scionsGoal 2 -Reduce the negative impact of high temperatures during summer/fall on fruit quality in apple and pear.Emerging tools for managing these issues will be tested across all major pome fruit growing regions in collaboration with grower partners. By understanding how heat affects fruit quality and focusing on sunburn and red color development, more effective models and management practices can be adopted that minimize these losses. Furthermore, the identification of genetic and transcriptional control of sunburn and red color development in segregating populations will support the selection of new cultivars better suited to high temperatures.Objective 2.1: Assess agronomic strategies that enhance red color and fruit quality or reduce fruit sunburnTask 2.1.1: Test plant growth regulator enhancement of red color and fruit quality for 'Honeycrisp' applesTask 2.1.2. Test the use of partial defoliation to improve red color and fruit quality in contrasting environmentsTask 2.1.3. Conduct applied trials on netting retraction, low volume evaporative cooling, and protectant sprays for sunburn mitigationTask 2.1.4. Assess pear sunburn risk under high and low tree densitiesObjective 2.2: Determine fruit physiological responses to high temperatures: acclimation and red color development in appleTask 2.2.1. Characterize apple fruit acclimation to high temperaturesTask 2.2.2 Quantify the impact of preharvest temperature on apple red color development and fruit qualityObjective 2.3: Uncover the genetic control of fruit sunburn susceptibility and red color development in apple Task 2.3.1. Characterize genetic control of fruit sunburn susceptibilityTask 2.3.2. Characterize genetic control of red color developmentGoal 3: Model the risks and economic impacts of temperature extremes to inform decision making by commercial apple and pear producers.In year 1, we will use existing data sets that can be immediately used for targeted model development, and in years 2-4, data generated from Goals 1 and 2 will be used to update models. These models will support economic cost-benefit analyses for management strategies identified in Goals 1 and 2. Tools and analyses will inform growers of risks for losses, guide risk management strategies, provide variety suitability maps, inform crop insurance products for apple and pear production, and feed into the Extension activities described in Goal 4.Objective 3.1: Develop and refine temperature-based predictive models for horticulturally relevant variables. Task 3.1.1. Assemble a database for model development and develop a software workflow pipeline.Task 3.1.2. Develop and iteratively refine predictive models for economically important variables related to heat and cold stressObjective 3.2: Quantification of current production risks and cost-benefit analysis for cultivar choices and mitigation strategies.Task 3.2.1. Conduct cultivar and management-specific spatial assessments of risks of losses from adverse temperaturesTask 3.2.2. Perform cost-benefit analyses of management strategies that reduce losses from adverse temperatures for current conditionsObjective 3.3: Prediction of future risks, their economic implications, and optimal risk management strategies under near future climate change scenarios.Task 3.3.1. Develop regional risk assessment tools for future apple and pear productionTask 3.3.2. Identify key combinations of temperature-related traits that reduce risk for losses under future climate conditionsTask 3.3.3. Conduct cost-benefit analyses of cultivar-specific management strategies that reduce losses caused by adverse temperatures under future climate conditionsGoal 4. Develop nationwide Extension programming to help growers manage orchard responses to adverse temperatures and prepare them for the effects of climate change on production.The development of national Extension programming will result in an apple and pear industry more prepared to face adverse weather events for fruit they grow now. The Extension team will facilitate regional knowledge transfer of effective management practices to limit losses caused by cold and heat stress. New knowledge acquired on cultivar-specific risks and management practices that reduce losses for producers will be communicated to the broader U.S. pome fruit industry. Predictive models will provide growers with information and decision-aid tools to select management practices and suitable cultivars for new orchards, while also producing scion and rootstock cultivar recommendations for future climates.Objective 4.1: Outreach to growers and other stakeholdersTask 4.1.1: Conduct a nationwide survey to assess risk thresholds for losses caused by adverse temperatures which are often difficult to quantify.Task 4.1.2: Coordinate regional field trials and demonstrations for applied management strategies to reduce temperature-related lossesTask 4.1.3: Connect Extension/outreach efforts for this project with national/regional Extension meetings and orchard toursObjective 4.2: Tools and training for using management practices and predictive toolsTask 4.2.1: Conduct fruit schools for cold and heat stress management in apple and pearTask 4.2.2: Produce decision-aid and climate tools that improve region-specific management strategies and cultivar selectionTask 4.2.3: Publish durable Extension products

Progress 09/01/24 to 08/31/25

Outputs
Target Audience:The target audience of this project are growers and industry professionals focused on apple and pear production acrossthe United States. There are more than $80 million of insurable losses to heat and cold events for apple and pear each year and growers have consistently prioritized the development of options to minimize these losses for their operations.Our project team encompasses the four major apple-producing states (accounting for more than 85% of total production) and two major pear-producing states (accounting for more than 90% of total US production. Many members of our project team have significant Extension or outreach responsibilities to their state apple and/or pear industries.We are also expanding our outreach to other states that produce apple and pears through the integration of the scientific advisory committee that extends across most of the other regions. We are also providing scientific information to academic and research groups who are seeking to better understand how hot and cold temperature events impact the apple and pear supply for U.S. consumers. The project team presented research and introduced the newly initiated project to more than 3000 industry professionals in the first year of the project. We anticipate this will increase in year 2 as research experiments and trainees progress in their respective programs. We also have an online component for this project. We have a website that will contain project information and guidance to find key project outputs and information. We also have a social media component that will be used to highlight research and Extension being done by the project team. We are seeking to increase the number of followers and website visits through enhanced outreach in year 2. Our social media had more than 11,000 impressions and 166 followers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Project team building The SPARC team has initiated monthly goal-specific meetings where we coordinate upcoming experiments, present on topics relevant to the group, and discuss results from completed experiments. These monthly meetings will continue for the duration of the project. These meetings have been useful for coordination of experiments, sharing new research, learning about new methods, and sharing information on theory and past research for trainees who are now a part of this project. We now have 2 graduate student FTE, 2 postdoctoral scientist FTE, and almost 4 scientist FTE funded on this project. These trainees will have the opportunity to share their research during monthly and annual meetings. They will also receive training in Extension and outreach communications from project team members during their period of employment at their respective institutions. We are in the planning stages of a heat related fruit school in early 2026 that will incorporate existing theory, identify gaps, and share applied research. This fruit school is targeted towards growers, industry professionals, graduate students, and other scientists working in this area of research. This school will help increase knowledge on understanding and mitigating heat-related events. How have the results been disseminated to communities of interest?Website development A public-facing SPARC website was developed in February 2025. The website highlights the project description, information about the team, upcoming events, news and media related to SPARC, and publications. Since the website became accessible to the public it has received 429 visits, with around 21% of visits being repeat visits. Grower and industry engagement In the first four months of the project, Project director, Lee Kalcsits, has introduced SPARC to industry stakeholders at regional, national, and international meetings. The total audience count for these grower-focused conferences(8) has exceeded 2000 people from across the United States, Canada, with attendance from other countries as well. The focus on these meetings has been U.S. grower engagement. Ashley Thompson also introduced SPARC to the Fresh and Processed Pear Committee at their annual review in February, 2025. Social media engagement Cultivation of a social media presence on the platform LinkedIn began in January 2025. Initial posts focused on introducing the SPARC website and researchers to gain awareness of the project. As more research and products are produced through the SPARC project, social media engagement will shift to highlight research updates, sharing of publications and driving traffic to the SPARC website to highlight resources. Since January 2025 the SPARC SCRI LinkedIn has gained 166followers and made 11,365impressions. Committee development The SPARC scientific and stakeholder advisory committees have both been finalized and formed. These committees will receive these quarterly reports and will participate in annual meetings. The stakeholder advisory committee is made up of key apple and pear industry people that are engaged in applied research and committed to improving profitability for apple and pear producers across the United States. The scientific committee will also be a conduit for extension communications that will extend the reach of our project. What do you plan to do during the next reporting period to accomplish the goals?Our project is heavilyfarmer focused and dedicated to providing novel options for reducing losses from cold and heat events for apple and pear. Our experiments seek to develop an understanding of how damage occurs, how genetics control how much loss occurs, and then what options the farmer has that can minimize losses when these extreme temperature events occur. The project team will continue to develop research in goals 1 and 2 as laid out in the project timeline. Experiments continue year-round focusing on timepoints that are important to apple and pear production that occur across all four seasons. We aren't anticipating any changes to the proposed experiments and activities described for year 2. Some of these experiments will reach two years of data by the end of year 2 and will be ready for preparing scientific and Extension publications that communicate this research to the grower community. Goal 3 will make more progress in year 2 than year since model parameter development was required in year 1 before the modelling and economics groups could start with their research. The Extension team will prepare a publication from the survey that was performed in year 1 of the project. This survey helped growers communicatethe risks of heat and cold events to their operations. The project annual meeting will take place on November 12-13, 2025. This will be a virtual event that will bring together the project team of over 40 scientists, technicians, and trainess with the scientific and stakeholder advisory committees for the first day to share project progress. Then, the second day will be focused on team efforts and project coordination for year 2 of the project. The project team is also organizing a heat fruit school that will be in-person in Washington state with a virtual option for those attendees who are not able to attend in person. This fruit school will occur in March 2026.

Impacts
What was accomplished under these goals? Goal 1. Reduce losses to apple and pear productivity and health from low temperature stress Apple rootstock and scion cold hardiness. Jason Londo has been evaluating the cold hardiness of apple scion and rootstock stem tissue using electrolyte leakage and oxidative browning methods. Additionally, he has been examining the impact of freeze damage on grafted apple tree growth and performance using controlled freezing assays and greenhouse studies. Dormancy initiation, chilling, and release in pear. Kelsey Galimba, Jessica Waite, and Ashley Thompson are characterizing the dynamics of both dormancy stage and cold hardiness for the three major US pear cultivars, from the onset of endodormancy in the fall until the bud break in the spring. They are doing this for both vegetative and floral portions of the tree, with the floral cold hardiness experiments extending past bud break and into the first stages of fruit development, when the fruitlet is still susceptible to frost damage. Genetic control of bud break and bloom in apple. Kenong Xu has been collecting bud break and bloom data from a USDA Malus (apple) collection in Geneva, New York, which comprises both domestic apples and wild relatives. Data collection activities started late March 2025 and ended by mid-June.As a result, the impact of our work will include: 1) greatly enhancing the understanding of the two important phenological traits in apple; 2) allowing efficient tools to be developed to accelerate the apple breeding process to rapidly release novel and climate resilient apple cultivars. Acclimation and deacclimation of apple under differing outdoor temperatures. Renae Moran conducted 1 to 9-day durations of exposure to cool, warm or freezing temperatures followed by measurements of cold temperature tolerance to -45 °C in Nov., Feb. and Mar. She compared gain or loss in hardiness in xylem, phloem and cambium in 2-year-old apple branches. In Feb. and Mar. she also measured hardiness in flower buds. Data can be used to develop cold hardiness models that estimate changes in hardiness according to outdoor ambient temperatures. Apple flower bud phenology at three temperatures. Sangeeta Sapkota, Renae Moran, and Todd Einhorn exposed apple flower buds collected at the dormant bud stage and measured the days to different stages of bud development in warm (20 °C), cool (10 °C) and cold (5 °C) temperatures to develop a degree-hour model. Frost protectants (Kumar, Moran, Kalcsits, Sapkota, Einhorn, Robinson, Lawrence). We tested the efficacy of three frost protectants during the pink bloom stage of apple at five locations throughout the United States. Materials were applied with an airblast sprayer, and flower clusters were then exposed to freezing temperatures. Flower temperature and flower survival were compared to an unsprayed control. Rootstock effects on scion chilling requirements. Gennaro Fazio grew and evaluated 150 rootstock breeding lines and advanced material for their ability to break bud after different dormancy chilling treatments. His team also collected xylem sap from several rootstocks that show differential ability to reduce the chilling requirement of scion varieties. Goal 2. Reduce the negative impact of high temperatures during summer/fall on fruit quality in pome fruit. Enhancing red color under warm temperatures in apple. Lailiang Cheng, Renae Moran, and Lee Kalcsits are conducting experiments to better understand the underlying physiological and horticultural factors that contribute to optimum red color development in apple. This research will add precision to the ability of growers to maximize red color development under challenging temperature environments during ripening. These experiments include: 1. Partial defoliation before fruit harvest in combination with postharvest foliar urea application to improve fruit color development while maintaining spur productivity. 2. Jasmonic acid application before fruit harvest to improve fruit color development. 3. Comparison of Royal Red and Firestorm strains with the original Honeycrisp in fruit color development. Understanding the physiology behind sunburn development and tolerance in apple. Jessica Waite was able to analyze data from FST (fruit surface temperature) monitoring of Cripps Pink last summer, and compare that to previous data from Honeycrisp, Granny Smith, and WA-38. She also worked with Kate Evans, Lee Kalcsits, and Chris Cook to plan heat stress experiments for Cripps Pink, Honeycrisp, and FST monitoring for the Cripps x Honeycrisp population for the 2025 summer, which will start in July. Lee Kalcsits's team has built control systems to run controlled sunburn experiments to determine cultivar and development-specific sunburn thresholds and acclimation mechanisms for apple.Our work seeks to find genes or DNA markers that are connected to dormancy transitions and heat stress/sun injury. Genetic control of sunburn susceptibility. Kate Evans, Chris Cook, Jessica Waite, and Lee Kalcsits started experiments for July and August to phenotype variability in segregating populations on susceptibility to sunburn. These include large-scale phenotyping of sunburn development in genetically variable seedling populations. The identification of genetic factors that contribute to sunburn susceptibility in apple will allow for better parental selection and more efficient characterization of selections that might be less susceptible to sunburn losses in semi-arid environments. Sunburn susceptibility of different pear orchard systems. Kelsey Galimba, Jessica Waite, and Lee Kalcsits are working on evaluating fruit sunburn on either high- or low-density pear systems and will be running those experiments in the summer 2025. These will focus on Bartlett in both Hood River and Wenatchee River production regions. Goal 3. Model the risks and economic impacts of temperature extremes to inform decision making by commercial apple and pear producers. Reviewing current models that predict heat and cold stress risk in apple. Kirti Rajagopalan and new Ph.D. student, Amir Birjandi have initiated a review paper focused on modelling development for tools that predict risk of damage from extreme cold and heat events. Unified fruit surface temperature model.Kirti Rajagopalan and her team with Paola Pesantez-Cabrera, Lee Kalcsits, and Ananth Kalyanaraman are developing a unified framework applicable across multiple fruit crops. The next step is model validation and testing with real-world data. Phenological modeling initiative. Kirti Rajagopalan is initiating a coordinated effort to compile phenological data across teams. This data will support the development of achill-overlap bloom model, which incorporates both chill and heat accumulation to better represent bloom timing. This addresses concerns from team members that heat-only models fall short in accurately predicting bloom phenology. Goal 4. Develop nationwide Extension programming to help growers manage orchard responses to adverse temperatures and prepare them for the effects of climate change on production. The extension group (Seifrit, Kalcsits, Sazo, Lavely, Thompson, Kumar, Hall) led by Dr. Sonia Hall gained IRB approval and fielded a survey to apple and pear growers in main production regions across the US at more than 10 conferences to understand their perceptions of impacts from heat and cold, the strategies they use to manage those impacts, changes they're perceiving in those impacts and information needs they have to better manage them. The group received 118 responses, with response quality (estimated by Qualtrics) of 94%. The survey closed May 23, 2025, with the last response collected on April 23, 2025. The Extension team has increased awareness efforts for the project through presentations to growers (Thompson) and podcasts (Seifrit, Kumar, Lavely, and Kalcsits).

Publications

  • Type: Conference Papers and Presentations Status: Other Year Published: 2025 Citation: Shanthanu Krishna Kumar, Lindsay Brown, 2025. A Preliminary Study on Peach Bud Freeze Protection with Cellulose Nanocrystal Sprays. Mid-Atlantic Fruit and Veg Conference.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2025 Citation: Kate Evans, 2025. Plant breeding from a pome fruit perspective. University of Hawaii at Manoa Brewbaker Lecture in Plant Science. Manoa, HI.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2025 Citation: Lee Kalcsits, 2025. Introducing SPARC: Strengthening pear and apple resilience to climate. International Tree Fruit Association. Rochester, NY.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2025 Citation: Lee Kalcsits, 2025. Mitigating damage from extreme temperatures in tree fruit. IRTA Invited Seminar. Girona, Spain.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2025 Citation: Lee Kalcsits, 2025. Sunburn mitigation in apples. Interior British Columbia Horticultural Show. Penticton, Canada.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2025 Citation: Jason Londo, 2025. Examining the potential role of freeze exposure in rootstock shank damage and tree decline. 68th Annual International Fruit Tree Association Annual Conference. Rochester, NY.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2025 Citation: Jason Londo, 2025. Apple rootstock cold hardiness, tree decline and climate change. Southwest Michigan Horticulture Days. Benton Harbor, MI.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2025 Citation: Jason Londo, 2025. Apple rootstock cold hardiness, tree decline and climate change. Nova Scotia Fruit Growers Association Annual Conference. Wolfville, Nova Scotia.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2025 Citation: Jason Londo, 2025. Examining the potential role of cold damage in rootstock shank damage and decline. 2025 Apple Tree Decline Summit. Hershey, PA (Online).
  • Type: Conference Papers and Presentations Status: Other Year Published: 2025 Citation: Jason Londo, 2025. Apple rootstock cold hardiness, tree decline and climate change. North Central Washington Apple Day. Wenatchee, WA (Online).
  • Type: Conference Papers and Presentations Status: Other Year Published: 2025 Citation: Lailiang Cheng, 2025. Nitrogen management for apple orchards. The Mid-Atlantic Fruit and Vegetable Convention. Hershey, PA.
  • Type: Other Status: Other Year Published: 2025 Citation: Ashley Thompson, 2025. Introducing SPARC: Strengthening pear and apple resilience to climate. Washington Tree Fruit Research Commission Pear Research Review. Hood River, OR.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2025 Citation: Ashley Thompson, 2025. Oregon Pear Extension Updates. Oregon State University Winter Horticulture Meeting. Hood River Oregon.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2024 Citation: Sonia Hall, 2024. �Qu� pasa cuando los extremos de temperatura ya no son extremos? (What happens when temperature extremes are no longer extreme?). Yakima, WA.